Use str.join
Ex:
l = [('A', 'A'), ('A', 'C'), ('A', 'H'), ('A', 'K'), ('C', 'C'), ('C', 'H'), ('C', 'K'), ('H', 'H'), ('H', 'K'), ('K', 'K')]
print(["".join(i) for i in l])
print("\n".join(["".join(i) for i in l])) #If you need it in separate lines
Output:
['AA', 'AC', 'AH', 'AK', 'CC', 'CH', 'CK', 'HH', 'HK', 'KK']
AA
AC
AH
AK
CC
CH
CK
HH
HK
KK